I. Technical Field
The present disclosure relates to metallocene derivatives, as well as to catalytic methods, processes and systems comprising such metallocenes, which can advantageously be used for olefin polymerization. The present disclosure also relates to metallocene activation methods, including methods that result in producing two different average molecular weight polymers simultaneously using a single metallocene and solid support.
II. Background
Metallocenes have proven to be effective catalysts in the production of higher molecular weight unbranched polymers using alkene monomers such as ethylene. While effective catalysts, current metallocenes are limited in the maximum average molecular weight of the resultant polymers, have limited activity, or lead to large amounts of long-chain branching. Therefore, the design of new catalysts to mediate these issues is of industrial importance. In many applications, the inclusion of two or more different molecular weight polymers within the same resin is important to achieve the desired properties for that material. Often, this mixture is achieved by physically mixing two different molecular weight polymers together to form a single material material. By combining the materials after the polymers have been generated can lead to imperfect mixing or the creation of gels and thus generate a material which is still at a molecular level heterogeneous. If the disparity between the two polymers' molecular weight or density is too great, the mixing process could fail to even produce a homogenous mixture. Development of a process which generates the different molecular weight polymers at the same time could lead to a better quality material. The production of the two polymers in the same reaction system would allow for improved mixing of the two molecules at the near molecular level helping to ensure homogeneity as well reducing the chances that gels would be formed within the polymer mixture.